This invention relates to a new and improved pre-calibrated, continuous flow, gas mixing system to be used in mixed-gas diving.
Conventional mixing systems are generally constructed from commercially available components. Necessary equipment includes a number of mixed gas cylinders required, an equal number of high pressure oxygen cylinders, a mixing manifold arrangement, an oxygen analyzer and an oxygen booster pump. Gases are mixed intermittently by the following lengthly procedure. First, the multi-cylinder mixing manifold is connected, then the proper sequence of valves must be opened to obtain an estimated inert gas mix. Next the pressure in the cylinders must be calculated after mixing. The next step requires opening the proper sequence of valves to obtain an estimated oxygen gas mix. The mixture is then allowed to set for 6 hours or the cylinder is tumbled to obtain a homogeneous mix. The resulting mixture must be analyzed to determine the oxygen percentage of the resulting mixture. Oxygen must then be added as necessary, reanalyzed and repeated as necessary until the desired mixture is obtained.
Another prior art commercially available continuous flow system cannot be used to fill high pressure cylinders. This electrically powered system supplies mixed gas directly to a diver or hyperbaric system at pressures up to 750 PSI. All components are exposed to high pressure oxygen, therefore gases must be dry and oil free to minimize risk of explosion.
Other prior art devices such as U.S. Pat. No. 3,593,735 to Reiher disclose a method and apparatus for maintaining a preselected oxygen partial pressure in breathing gas supplied to a diver under an abnormal pressure. A mixing tank with separate inputs is provided to receive and blend together oxygen and filler gas according to a preselected ratio as breathing gas is withdrawn from the tank by a diver. This invention does not combine oxygen and air as the instant invention does. U.S. Pat. No. 4,206,753 discloses a method and apparatus for mixing gases wherein oxygen is mixed into hydrogen for use as a breathing gas for divers, pressure chambers, etc., in precise and regulated amounts. The oxygen is injected into the carrier gas from an injection jet. The carrier gas is circulated in repeated passes past the oxygen injection jet in a conduit system. This invention requires hydrogen as a carrier gas and does not combine oxygen and air as the subject invention does.
Unlike the prior art devices, the instant invention does not rely on electric power. The gas mixing console itself does not require power. The compressor can be powered by either gas or electricity. Unlike commercially available continuous flow mixing systems, only the injection system of the instant invention is exposed to pressurized oxygen.